Layne Adams, Ph.D.
Population biology and predator/prey relationships of Alaskan large mammals.
Professional Experience
2022 - Present Research Wildlife Biologist Emeritus USGS, Alaska Science Center, Anchorage, Alaska
1993 - 2022 Research Wildlife Biologist USGS, Alaska Science Center, Anchorage, Alaska
1985 - 1993 Regional Research Wildlife Biologist, US National Park Service, Anchorage, Alaska
1980 - 1985 Wildlife Management Biologist, Bureau of Land Management, Fairbanks, Alaska
Education and Certifications
Ph.D. 1996 University of Minnesota, St. Paul, MN Wildlife Conservation
M.S. 1981 Colorado State University, Ft. Collins, CO Wildlife Biology
B.S. 1976 Colorado State University, Ft. Collins, CO Wildlife Biology
Affiliations and Memberships*
IUCN Species Survival Commission, Wolf Specialist Group (2001-2013)
The Wildlife Society
Arctic Institute of North America
American Society of Mammalogists
Science and Products
Range expansion of moose in arctic Alaska linked to warming and increased shrub habitat
Estimating demographic parameters using a combination of known-fate and open N-mixture models
Changing Arctic ecosystems: resilience of caribou to climatic shifts in the Arctic
Environmental and physiological influences to isotopic ratios of N and protein status in a montane ungulate in winter
Climate-driven effects of fire on winter habitat for caribou in the Alaskan-Yukon Arctic
Lack of sex-biased dispersal promotes fine-scale genetic structure in alpine ungulates
Range overlap and individual movements during breeding season influence genetic relationships of caribou herds in south-central Alaska
Diversity of nitrogen isotopes and protein status in caribou: implications for monitoring northern ungulates
An isotopic approach to measuring nitrogen balance in caribou
Fire, grazing history, lichen abundance, and winter distribution of caribou in Alaska's taiga
Characteristics of foraging sites and protein status in wintering muskoxen: insights from isotopes of nitrogen
Wolves will not provide small-scale ecological restoration
Science and Products
- Science
- Data
- Publications
Filter Total Items: 59
Range expansion of moose in arctic Alaska linked to warming and increased shrub habitat
Twentieth century warming has increased vegetation productivity and shrub cover across northern tundra and treeline regions, but effects on terrestrial wildlife have not been demonstrated on a comparable scale. During this period, Alaskan moose (Alces alces gigas) extended their range from the boreal forest into tundra riparian shrub habitat; similar extensions have been observed in Canada (A. a.AuthorsKen D. Tape, David D. Gustine, Roger W. Reuss, Layne G. Adams, Jason A. ClarkEstimating demographic parameters using a combination of known-fate and open N-mixture models
Accurate estimates of demographic parameters are required to infer appropriate ecological relationships and inform management actions. Known-fate data from marked individuals are commonly used to estimate survival rates, whereas N-mixture models use count data from unmarked individuals to estimate multiple demographic parameters. However, a joint approach combining the strengths of both analyticalAuthorsJoshua H. Schmidt, Devin S. Johnson, Mark S. Lindberg, Layne G. AdamsChanging Arctic ecosystems: resilience of caribou to climatic shifts in the Arctic
The U.S. Geological Survey (USGS) Changing Arctic Ecosystems (CAE) initiative strives to inform key resource management decisions for Arctic Alaska by providing scientific information and forecasts for current and future ecosystem response to a warming climate. Over the past 5 years, a focal area for the USGS CAE initiative has been the North Slope of Alaska. This region has experienced a warmingAuthorsDavid D. Gustine, Layne G. Adams, Mary E. Whalen, John M. PearceEnvironmental and physiological influences to isotopic ratios of N and protein status in a montane ungulate in winter
Winter severity can influence large herbivore populations through a reduction in maternal proteins available for reproduction. Nitrogen (N) isotopes in blood fractions can be used to track the use of body proteins in northern and montane ungulates. We studied 113 adult female caribou for 13 years throughout a series of severe winters that reduced population size and offspring mass. After these sevAuthorsDavid D. Gustine, Perry S. Barboza, Layne G. Adams, Nathan B. WolfClimate-driven effects of fire on winter habitat for caribou in the Alaskan-Yukon Arctic
Climatic warming has direct implications for fire-dominated disturbance patterns in northern ecosystems. A transforming wildfire regime is altering plant composition and successional patterns, thus affecting the distribution and potentially the abundance of large herbivores. Caribou (Rangifer tarandus) are an important subsistence resource for communities throughout the north and a species that deAuthorsDavid D. Gustine, Todd J. Brinkman, Michael A. Lindgren, Jennifer I. Schmidt, T. Scott Rupp, Layne G. AdamsLack of sex-biased dispersal promotes fine-scale genetic structure in alpine ungulates
Identifying patterns of fine-scale genetic structure in natural populations can advance understanding of critical ecological processes such as dispersal and gene flow across heterogeneous landscapes. Alpine ungulates generally exhibit high levels of genetic structure due to female philopatry and patchy configuration of mountain habitats. We assessed the spatial scale of genetic structure and the aAuthorsGretchen H. Roffler, Sandra L. Talbot, Gordon Luikart, George K. Sage, Kristy L. Pilgrim, Layne G. Adams, Michael K. SchwartzRange overlap and individual movements during breeding season influence genetic relationships of caribou herds in south-central Alaska
North American caribou (Rangifer tarandus) herds commonly exhibit little nuclear genetic differentiation among adjacent herds, although available evidence supports strong demographic separation, even for herds with seasonal range overlap. During 1997–2003, we studied the Mentasta and Nelchina caribou herds in south-central Alaska using radiotelemetry to determine individual movements and range oveAuthorsGretchen H. Roffler, Layne G. Adams, Sandra L. Talbot, George K. Sage, Bruce W. DaleDiversity of nitrogen isotopes and protein status in caribou: implications for monitoring northern ungulates
Nutritional condition is an important determinant of productivity and survival in caribou (Rangifer tarandus). We used samples of excreta (n = 1,150) to estimate diet composition from microhistology and 2 isotopic proxies of protein status for 2 ecotypes of caribou in 4 herds in late winter (2006–2008). Isotopes of nitrogen (δ15N in parts per thousand [‰]) from excreta samples (urea, diet, and bAuthorsDavid D. Gustine, Perry S. Barboza, James P. Lawler, Layne G. Adams, Kathy L. Parker, Steve M. Arthur, Brad S. ShultsAn isotopic approach to measuring nitrogen balance in caribou
Nutritional restrictions in winter may reduce the availability of protein for reproduction and survival in northern ungulates. We refined a technique that uses recently voided excreta on snow to assess protein status in wild caribou (Rangifer tarandus) in late winter. Our study was the first application of this non‐invasive, isotopic approach to assess protein status of wild caribou by determiningAuthorsDavid D. Gustine, Perry S. Barboza, Layne G. Adams, Richard G. Farnell, Katherine L. ParkerFire, grazing history, lichen abundance, and winter distribution of caribou in Alaska's taiga
In the early 1990s the Nelchina Caribou (Rangifer tarandus) Herd (NCH) began a dramatic shift to its current winter range, migrating at least an additional 100 km beyond its historic range. We evaluated the impacts of fire and grazing history on lichen abundance and subsequent use and distribution by the NCH. Historic (prior to 1990) and current (2002) winter ranges of the NCH had similar vascularAuthorsWilliam B. Collins, Bruce W. Dale, Layne G. Adams, Darien E. McElwain, Kyle JolyCharacteristics of foraging sites and protein status in wintering muskoxen: insights from isotopes of nitrogen
Identifying links between nutritional condition of individuals and population trajectories greatly enhances our understanding of the ecology, conservation, and management of wildlife. For northern ungulates, the potential impacts of a changing climate to populations are predicted to be nutritionally mediated through an increase in the severity and variance in winter conditions. Foraging conditionsAuthorsDavid D. Gustine, Perry S. Barboza, James P. Lawler, Stephen M. Arthur, Brad S. Shults, Kate Persons, Layne G. AdamsWolves will not provide small-scale ecological restoration
Licht and colleagues (BioScience 60: 147–153) proposed a paradigm shift in wolf management to include the introductions of small, highly manipulated groups of wolves (Canis lupus) to confined natural areas to facilitate ecosystem recovery. Certainly, reductions or losses of apex predators from many regions worldwide have had profound effects on ecosystem characteristics (Soulé et al. 2003). NumeroAuthorsJerrold L. Belant, Layne G. Adams - News
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government